The invention relates to a vacuum cleaner with a suction nozzle and a handle which is coupled to the suction nozzle during operation, said suction nozzle being provided with electrical drive means for exerting a driving force on the suction nozzle, while the vacuum cleaner comprises a detector by means of which at least a direction is controllable in which the drive means exert the driving force on the suction nozzle during operation.
In a known vacuum cleaner of the kind mentioned in the opening paragraph, the electrical drive means of the suction nozzle comprise an electric motor which is arranged in the suction nozzle for driving a set of drive wheels with which the suction nozzle rests on a surface to be cleaned during operation. The detector of the known vacuum cleaner comprises a switch having three positions which controls a direction of rotation of the motor and which is in contact with the surface to be cleaned during operation. If a user of the vacuum cleaner pushes the suction nozzle in a forward direction, the switch is forced into a first extreme position under the influence of the friction between the switch and the surface to be cleaned, in which position the motor drives the drive wheels with a substantially constant speed in a direction of rotation which corresponds to the forward direction. If the user pulls the suction nozzle in a backward direction, the switch is forced into a second extreme position under the influence of said friction, in which position the motor drives the drive wheels with a substantially constant speed in a direction of rotation corresponding to the backward direction. If the user keeps the suction nozzle in a fixed position on the surface, the switch is displaced to an intermediate position situated between said two extreme positions, in which the motor does not rotate. The electrical drive means thus exert a driving force on the suction nozzle via the drive wheels in a direction of movement of the suction nozzle desired by the user. A pushing or pulling force to be exerted on the handle by the user is considerably reduced thereby.
It is a disadvantage of the known vacuum cleaner that the drive wheels are driven with a substantially constant speed. As a result, the driving force delivered by the drive means will not lead to a speed of movement of the suction nozzle over the surf-ace to be cleaned desired by the user in many cases. If the user wishes to reverse the direction of movement of the suction nozzle, moreover, the user must initially displace the suction nozzle in the desired new direction of movement with a comparatively great pushing or pulling force until the switch is operated under the influence of the friction between the switch and the surface to be cleaned and the direction of rotation of the drive wheels corresponds to the desired new direction of movement. The ease of use of the known vacuum cleaner is adversely affected thereby.